Elevator heat treatment furnace



June 17, 1958 w. R. GILBERT 2,839,284

ELEVATOR HEAT TREATMENT FURNACE Filed April 11, 19 55 2 Sheets-Sheet 1 June 17, 1958 w R. GILBERT 2,839,234

ELEVATOR HEAT TREATMENT FURNACE Filed April 11, 1955 v 2 Sheets-Sheet 2 IN V EN TOR.

Patented June 17, 1958 ELEVATOR HEAT TREATMENT FURNACE Wesley R. Gilbert, Cranston, R. I., assignor to C. i. Hayes, Inez, a corporation of Rhode Island Application April 11, 1955, Serial No. 500,362

1 Claim. (Cl. 263-37) The present invention relates to the heat treatment of metal and the like, and has particular reference to a novel construction for an elevator heat treatment furnace.

The principal object of the invention is to provide a novel furnace construction whichis particularly suitable for the heat treatment of large metal articles.

Another object of the invention is to provide a novel furnace construction for bright annealing large metal objects in a heat treatment atmosphere of hydrogen or containing hydrogen, the atmosphere being kept free from contamination, and free from explosion hazard and excessive loss of atmosphere during the input of work to be heat treated and the egress of the heat treated work.

A further object of the invention is to provide an elevator type heat treatment furnace in which the heat treatment chamber is in superimposed vertical relation to the cooling chamber.

With the above and other objects and advantageous features which will become apparent as the description proceeds, the invention consists of a novel arrangement of parts more fully disclosed in the detailed description thereof, in conjunction with the accompanying drawings, and more specifically defined in the claim appended thereto.

In the drawings,

Fig. 1 is a vertical sectional detail showing a side view of the upper portion of a preferred furnace construction which embodies the invention;

Fig. 2 is a vertical sectional detail of the lower portion of the furnace of Fig. 1;

Fig. 3 is a vertical sectional detail of the rear portion of the furnace of Fig. l; and

Figs. 4 and 5 are reduced detail sections on the lines 44 and 55 of Fig. 1.

The heat treatment of large metal articles requires a large inlet and large outlet, whereby a horizontal type furnace is high in initial and in operating cost; excessive loss of heat enveloping atmosphere from the heat treatment chamber is also diflicult to reduce. Further, when the heat treatment is bright annealing of stainless steel or other metals at elevated temperatures such as 2100 F., the enveloping atmosphere is hydrogen or contains hydrogen, and an explosion hazard exists, and requires special safeguards to reduce contamination and to lower the temperature of gases seeping from the heat treatment and the work cooling chambers.

I have therefore devised a heat treatment furnace of vertical type, with a lower loading and unloading chamber having a door through which work to be heat treated is inserted and through which cooled heat treated work is removed, an intermediate chamber superimposed on the lower chamber and provided with water-cooled walls, and an upper heat treatment chamber, the work being moved upwardly from the lower chamber to the heat treatment chamber and then downwardly to the cooling chamber and then to the lower chamber. I provide a door between the heat treatment chamber and the cooling chamber, whereby downward seepage of heat treatment atmosphere is minimized.

Referring to the drawings, the elevator furnace 10 includes an upper heat treatment chamber 11, an intermediate cooling chamber 12, and a lower loading and unloading chamber 13 with a door 14, the chamber 13 being spaced a distance A above the floor 15 bringing the door 1 to a reasonable loading and unloading level of approximately 36 inches. The furnace is supported by standard type housing or girder elements, not illustrated.

The heat treatment chamber 11 is preferably circular, of dome type, with insulating walls 16 having wall heating units. A retort 17, preferably of A1, inch Inconel, conforms to the shape of the heat treatment chamber interior, but is spaced from the walls and the dome to provide a space 18, whereby the heat of the wall heating elements is circulated over the retort dome. Heat treatment atmosphere is supplied through a tube 123, preferably of /2 inch lnconel, which extends through rings 20 on the retort in the space '18 and is curved over and welded to the retort dome for down few of atmosphere through the heat treatment chamber.

The retort 17 is preferably reduced at the throat 21 to restrict radiation loss down into the cooling chamber, and is provided with support ribs 22 and insert insulation 23, whereby the retort may be removed bodily f om the heating chamber should repairs to the Wall heating elements be required. A removable closure 24 is provided below the throat 21, and includes two sliding doors 25, 26 which are preferably of rectangular shape and slide in a Water-cooled housing 27.

The cooling chamber 12 is preferably of circular form, and is built up of small sections 28, 29 and 30 which have end flanges bolted together to facilitate replacement, the sections being individually water cooled to obtain circulatory cooling without too extended a flow path in any one circuit. If desired, a circular manifold, not shown, may be inserted between the cooling chamber and the retort, or at any other suitable position, to spray the top part of the workload.

The cooling chamber is preferably of the same inner diameter as the retort throat, to permit welding of the retort and the cooling section, which could then be removed as a unit for furnace repairs.

The loading and unloading chambers 13 are preferably of circular form conforming to the interior diameter of the cooling section, and flanged at the upper end to be bolted to the lower flanged end of the lowermost cooling section. The door 14 is preferably rectangular and hinged to the upper end of a circular hood section 31 shaped to angularly position the door as illustrated.

As is clearly shown in Fig. 3, the inner surfaces of the chamber 13, the cooling chamber 12, and the heat-treatment chamber throat 21 are in vertical alignment, and

provide a vertical passageway 32 through which an elevator platform 33 and an elevator shaft 34 are readily movable. The elevator 33 is preferably a cast alloy base, as it forms the work load support during heat treatment.

The work is preferably set on a cast alloy support 35 seated on the elevator 33, which is equipped with polished steel alloy reflectors 36 for throwing the heat upwardly; similar reflectors 37 are positioned on the doors 25, 26, which are preferably edge recessed to seal around the upper portion of the elevator shaft 34 when the Work is being heat treated. A skeleton frame 38 of open grid work and equipped with downwardly directed polished heat reflectors 39 may be positioned over the top plate 49 of the support 35, to baffle the inflowing atmosphere gas and to direct gas and heat over the work; when the work is lowered into the cooling chamber the frame 38 and its reflectors 39 facilitate cooling of the top of the work load. The elevator shaft 34 may be water cooled if desired, by providing ,inlet and outlet connections which are below the door 14 when the elevator'is in work heating position.;;:= r i V The operationof the elevator furnace may now be explained. Work to be heat treated 'is inserted'through the door 14 and the support 35 and the frame 38 is placed overthe work; the elevator is then raised to position the work in the heat treatment chamber, the doors 25, 26 being first opened for the work entry and then closed to retain the heat treatment atmosphere in the chamber 11.

, When the work has been heat treated the doors 25, 26 a are opened and the work is lowered to seat in the cooling Gil in the size, shape and arrangement of the part's m'ay'be made to meet different requirements, without departing from the spirit and the scope of the invention as defined in the appended claim. a r

I claim:

cles in a hydrogen atmosphere or the like, said furnace comprising an upper heat treatment chamber, a cooling chamber and a lower loading and unloading chamber, said cooling chamber being intermediate the upper and lower chambers, said heat treatment chamber having a retort spaced from the walls thereof, said retort having a throat portion, said throat portion and the inner walls of the cooling chamber forming a vertical passageway, said retort andtsaid passageway'comprising a continuous, unbroken, air-tight enclosure whereby to prevent contamination of said heat treatment and cooling chamber by inwardly seeping air.

References Cited in the file of this patent UNITED STATES PATENTS 

